Operation & Software Manual
182
Direct Drives & Systems
Chapter C: System functions ETEL Doc. - Operation & Software Manual # DSC2P 903 / Ver. F / 3/6/05
13.8 RTI: Real-Time Interrupts
A Real-Time Interrupt (RTI) allows the execution of an immediate function. The sequence execution may jump
to a defined label, under some conditions. The RTI are tested each sti (each 166.67µs for the DSC2P/DSC2V
or each 500µs for the DSCDP, DSCDL and DSCDM). There are different types of RTI, but each of them can
be programmed only once. A maximum of 8 RTI can be programmed in the controller and they are all different
from each other.
Caution: RTI functions take a lot of calculation time on the controller's micro-controllers.
RTI definition: A RTI is a set of data which defines the conditions for a function to be activated and
executed at each cycle as far as they are validated (parameter K191) and enabled
(parameters K190 and K192).
A RTI defines the following points:
• The conditions to test (in order to activate a RTI)
• The operations to carry out when a RTI is executed
• The label where the sequence has to jump in case of execution
Functioning principle:
The user sets the RTI he will use with the corresponding parameters. He declares this RTI valid (1). From this
moment onwards, the activation conditions (2) of the valid RTI are tested. This test proceeds increasingly
from the lowest line number of the RTI table where they are stored (refer to §13.8.1.1
). As soon as the test
condition is true, the RTI is activated, independently from the fact that the test condition remains true or
becomes false. If the RTI is enabled (3), the RTI is executed (4).
Definitions:
1) Valid: A RTI is declared valid by setting the corresponding bit in parameter K191 (refer to §13.8.3.1
). It can
be declared valid only if its type, mode, label and parameters define a coherent function (refer to §13.8.1
).
2) Active: A RTI is active if its activation conditions have been or are true. The RTI automatically changes to
a valid non active RTI when it is executed.
3) Enable/disable: As the functioning of the interrupts on a micro-controller, the RTI can be 'enabled ' or
'disabled'. A RTI can become enabled (parameter K190) only when the controller is in the RTI enable mode
(RIE). Furthermore, the RTI table line itself must be set as enable in parameter K192.
4) Executing: This action consists in executing the preset functions of a RTI when the RTI is in an active and
enable mode. If the RTI label is set, the execution of the sequence goes on from the specified label. In the case
of a jump to a label, the controller automatically disables the RTI (automatic execution of command RID).
Note: A RTI must be valid, enabled and active to be executed (refer to §13.8.4
).
Available on DSC2P DSC2V DSCDP DSCDL DSCDM
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